一器双行气力式油麦兼用精量排种器籽粒运移规律研究

The steps to seeding rapeseed and wheat are similar during continuous period in the middle and lower reaches of the Yangtze River. However, current sowing machine was designed only for one species. Thus, a pneumatic precision seed-metering device was designed to work for both rapeseed and wheat seeds sowing into two rows. The purpose of this proposal is focus on the migration principle of the two kinds of seeds in the device. The first aim is to measure the mechanical and physical characteristics of the seeds. The second one is to analyze and generate the migration and control strategy of rapeseed and wheat groups in the filling room by means of the high-speed photography technology and discrete element method. The third one is to investigate the pneumatic characteristic of the metering system and the functional relation between the force on the seed and main structure as well as operating parameters of the system. Path planning of the seeds on stream of delivery and discharge process will be discussed by its Trajectory analysis. Additionally, the influences of the seeding performance of the device from the structure and operating parameters will be assessed to derive a fault tree model and a fuzzy evaluation model. The constraint and migration condition about the seeds in the seeding processes will be investigated. As a further step, the construction of some special commonness and individuality mechanisms of the prototype will be redesign. The results of the project would illustrate the process of rapeseed and wheat seeds from group to single one orderly. It also could offer reference for optimization design and performance improving for the dul-purpose precision seed-metering device.

针对长江中下游地区油菜、小麦农艺播期毗邻且工序相似，但缺乏兼用型精量播种农机装备的现实问题，围绕提出的一器双行气力式油麦兼用精量排种器，研究适应于两种籽粒单粒有序排种的约束运移规律。分析测试油菜、小麦籽粒机械物理特性；通过充种环节籽粒群运移高速摄影与离散元分析，研究充种量恒定控制机制；开展排种器气流通路实时监测与仿真分析，构建吸种、投种环节种子作用力与排种器结构、运行参数的关系模型，并进行基于籽粒运移轨迹分析的排种路径规划；以单粒均匀排种为顶事件开展排种过程故障树分析及影响因素模糊综合评判，建立排种器性能预测评价模型，探明两种籽粒在单粒有序转变过程中自由度和运移约束的共性、非共性边界条件，并开展适应于油菜、小麦兼用排种的排种器结构优化研究。项目的实施将为揭示排种系统与籽粒间的相互作用过程和作用、深化气力式精量排种技术研究提供基础理论，为开发油麦兼用精量播种机提供排种关键技术与核心部件。

在长江中下游地区油菜小麦种植生产实践中，要提高油菜小麦机械化水平，实现油菜、小麦生产的全程机械化，关键环节是开发高效适用的油菜小麦兼用型的播种装备，其核心内容是油麦兼用型排种技术与装置。本项目针对目前缺乏油麦兼用型精量播种装备的现实问题，围绕一器双行气力式油麦兼用精量排种器，开展其气力系统特性与排种过程研究、排种器结构改进与创新。主要研究内容包括测试分析了油菜、小麦的机械物理特性，分析了基于农艺要求的排种器故障模式影响及危害度；试验研究了排种系统的气力特性，构建了气压关系与排种系统参数关系模型，为气力式精量排种系统的结构优化与快速设计提供参考，提出了溢流释压稳压控制方法，将排种器气室正压、负压偏差率分别降低45%和110%，排种器的排种量变异系数减小2.68%，为播种机设计、气力式排种系统性能优化提供参考；研究了一器双行排种器的充种、投种与导种过程籽粒运移规律，其两行油菜排种合格指数达89.99%，两行小麦排种合格指数均为74.58%；排种过程研究表明气吸式吸种，单粒成功率可达92%以上，但通过导种管导种会大幅度降低播种均匀性，合格指数下降至70%以下，通过设计的带式主动导种装置可显著提高排种性能，排种器合格指数达85%以上；在一器双行排种器研究基础上，设计了一器六行内充种集排式排种器，运用高速摄影和3D打印技术优化设计了导种口结构，使集排器单行合格指数达90%以上。.上述研究对气力式排种系统的快速设计与气力式播种机排种性能的优化提升、油菜小麦兼用型播种机的开发有重要的理论意义和实际指导意义，对于其他作物种子的气力式精量排种理论研究、兼用型排种技术研究具有重要的理论参考价值。